In recent years, there is a demand for recycling resin products used in electric equipment and the like for the purpose of recycling resources. A lot of resin products used in electric equipment have their surfaces covered with a metal coating, which has to be removed when recycling resins.
Conventionally, it has been proposed to put a resin product with a metal coating into hot water so as to heat the same, thereby removing the metal coating (see, for example, Patent document 1). More specifically, the resin product, whose metal coating provided on its surface is cut with a cutter or the like previously, is heated in hot water with a temperature of 70° C. or higher for several hours, and then the metal coating is removed with running water.
Further, the following method also has been proposed to recover resins from a resin plate with a metal coating. That is, the resin plate provided with the metal coating initially is rolled, then the rolled resin plate is brought into contact with hot water or steam so as to allow resins to swell, the resin plate is pressed further, and then the metal coating is removed with running heated water (see, for example, Patent document 2).    Patent document 1: JP 5(1993)-345321 A    Patent document 2: International Publication No. 96/12598
However, although the above-mentioned conventional methods are capable of removing a metal coating with a relatively low adhesion strength, such as a vapor deposited film, it is difficult to remove a metal coating with a large thickness and a high adhesion strength, such as a plating film for ornamental purposes. Moreover, since the above-mentioned conventional methods include treatment with hot water, which makes resins swell, dehydration is required for recycling of resins.